Decoherence Budgets for Large-Molecule Interferometry with a Planck-Scale Noise Floor

This paper builds a decoherence budget for large-molecule matter-wave interferometry and adds a parametrised Planck-scale contribution to the familiar gas-collision and thermal-emission terms. Even with the dimensionless strength of the Planck term set to unity, its rate is 3.678e-13 per second and the fringe visibility after a ten-millisecond flight remains 1.0000; at a strength of one hundredth the rate falls to 3.678e-15 per second. Environmental decoherence dominates by many orders of magnitude in every realistic instrument. Planck-scale decoherence, in this parametrisation, cannot explain any observed visibility loss in molecular interferometry and cannot be detected there without an enhancement mechanism. The study is simulated and computed from stated assumptions; it is not a measurement.